A method of treating cardiac arrhythmia in a heart, including (i) determining that cardiac tissue is viable but with reduced innervation； and (ii) ablating the tissue to reduce a prevalence of arrhythmia in said heart. Optionally, the determining comprises detecting portions of heart wall which lack electrical activity. Optionally, at least some tissue which is viable but lacks nervous control is ablated, for example, to reduce or avoid arrhythmia.
